Dangers of underloading pistol cartridges (9mm)

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pathdoc

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Okay, after a long absence because of plenty of other things that got in the way, I'm about to take the plunge and start loading for 9mm Parabellum (i.e. Luger). I have all the ingredients, I have minimum and maximum load data for my powder and bullets (directly from the mouths of the bullet maker's technical experts, so I reckon I'm safe there), and all is in readiness.

So the question: apart from the obvious problems - failure to cycle and failure of the bullet to exit the barrel, the latter of which I would be checking for VERY carefully - is there actually any danger to be had from under-loading by a few tenths of a grain? Certainly I know that slow powders in large rifle cases have that strange detonation issue, but surely a case with as (relatively) little room in it as 9mm Para shouldn't have a problem in that regard.

I probably won't be loading more than five to ten rounds in each increment, and I'll probably be stopping a couple of tenths away from maximum in any case. As I see it, unless I'm doing precision target shooting and until I get a whole lot better, a tenth or two either way probably isn't going to make any practical difference to bullet performance.
 
Don't worry about it. If you are using powders popular for 9x19, a few tenths of a grain won't have a huge effect. Now, I wouldn't play "How low can you go?". I'm sure someone has, but why bother. FWIW, published starting loads for Barnes 115's barely cycle the action of my full size M&P. No ill effects, but kind of a waste of powder and shot.
 
^^^

This, just have fun and stay within the boundaries of the published materials.

Welcome to the addiction!
Tony
 
I'm curious why you have a need to load below the published data?

What is the purpose of this ammunition? I'm also curious what powders n bullets you plan on using? The most clear answers come from having the most clear information.

Slow powders (talking pistol here; and nothing to do with rife detonations, etc.) can be problematic when underloaded. Ignitions become inconsistent; along with subsequent results. Then there's powder fouling, soot, unspent propellent flakes, etc. 9mm Luger, being a small case, lends itself to a clean burn. None-the-less, a sooty under-pressure round can still be crafted :p.

I think sometimes we loaders forget that pressure is a good thing (to a point, of course). Those of us who most frequently load for low-power pure target applications (and minimum Power Factor in competitions) are often faced with the problem of low pressure and the challenge becomes finding ways to increase pressure, while maintaining low velocity/recoil.
 
My chosen powder, because it's what I have, is 700X. My projectiles are 115gn Hornady and 124gn Winchester FMJ. Intended use is plinking and trying to put speed and consistency together. I'm not so much interested in plumbing new lows (so to speak) as making sure there are no unexpected surprises if I throw a short charge.

At the distance I'll be testing these reloads, missing won't be an issue and the targets will grow green splotches when the bullets hit, so I'm not afraid of overlooking a squib if I get a failure to cycle. (This is what I love about shotgunning; even if I don't break the bird, 99.9% of the time I can see the wad sailing off into the distance and can be pretty sure there are no surprises left in the barrel :p ).

Loads will get heavier as I get more confident with the process, but as it's all new to me (first self-loader of any type, first straight case of any type, first pistol cartridge of any type), I'm loath to work up to maximum in any sort of hurry and would rather err on the low side.
 
One precaution worth taking with very light loads is, when testing them only load the magazines with one round at a time.
Just a thought.
 
I've been reloading for awhile now but just stared reloading pistol 9mm & 45acp early last year . I had some of the same concerns , maybe not as much as you do to the fact I'd already been loading for rifles . Still I found my general experience in shooting handguns helped . Always work up from minimum and when the charges increase how the gun react to those increases is quite telling . I can start to feel it in my palm , recoil gets a little snappy maybe a little torque is introduced and brass can start flying much farther then normal .

If you're not sure what those feelings are you can take some factory ammo with you and compare how the gun reacts with a standard factory charge . You can then compare if your loads have more or less of the symptoms above . Now that's not to say the above is a standard to watch for . Just some things I've observed and or read about .

One of the oddest feelings I had was the first time I shot Titegroup in 9mm at minimum charge and the subsequent next charge . It's hard to explain but it felt more like the bullet was spit out of the firearm rather the blasted out . Once I hit the mid charge range it was a more traditional feeling .
 
The greatest risk with 700X in light pistol loads is bridging of the large flakes.
I quit using 700X for anything less than .45 ACP Major after getting the occasional one grain drop when loading .38 and 9mm.
I was able to use it in 9mm during The Panic by putting a vibrator on the powder measure.
Some loaders report no trouble.
 
I load a lot of 700x in 9 mm and like it a lot, but it can be a problem metering due to the flakes bridging. I have the Lee PPM, Auto Drum, Pro Disc, and Lyman 55 measures and have found the PPM works best. But it does require a certain procedure to be very consistent. I just tap the drum 3 times on both the upstroke and downstroke using my finger and get great results. I shoot a lot of 124 gr Copper coated bullets from Extreme Bullets and am about the mid range of jacketed data with great results. Of course this is in my guns, YMMV.
 
It's pretty common to overthink this whole thing when it come to finding the "perfect" load for our pistol reloads. For close range, (25 yd or less) off hand shooting, pick a load in the middle of the spectrum, and have a ball. Safety and function will be achieved, and life will be happy. jd
 
Pretty much an echo of what others have said. As the charge is decreased the first issue you will encounter is the pistol not cycling. You will probably have to go lower than that to stick a bullet in the barrel. So as long as you are paying attention you'll be OK. Some people even load to the minimum (plus a little cushion for cold temps and normal variation) to save wear and tear and a few tenths of a grain in powder costs.
 
700-X is okay in 9mm

I LOVE 700-x in .45 ACP, and thought I'd try it in 9x19. It worked okay, but the bridging thing made me nervous, so I got obsessive about checking powder levels in the cases. It slowed me down enough that I decided my remaining 700-X would get used up in something else.

I noticed that 700-X worked best (no bridging & better groups) with charge weights > 4.0gr. This means lighter bullets, etc. One of my big attractions to 700-X in .45 ACP & .38 Spl. is that it burns so very cleanly, and it did the same in 9x19mm. A senior-citizen skeet & trap shooter (who is 20 years my senior and can STILL shoot rings around me) was the one who recommended 700-X to me, in the first place, commenting on how clean-burning it was in shotguns. It didn't take me very many rounds of .45 ACP for me to see his point.

The darned bridging thing just made me hyper-vigilant & slowed my ammo production, so I went back to using Unique/Herco/AA#5 & similar powders in it. Charge weights are sufficiently large that each powder meters, at worst, well ENOUGH (although AA#5 is particularly nice), and I can flat crank out the ammo, once I get myself set up in good form.
 
Here is one thing to keep in mind closely as you go forth...

It sounds like you are planning to be very cognizant of going too light and sticking a bullet in the bore in 9mm. This is an extremely good idea. If it does happen, obviously, everything needs to stop and you need to get it out of the bore before doing ANYTHING else with that handgun. We are all in agreement and you will be vigilant in looking for it. That's great.

In 9mm (and all semi-auto pistols) you've got a chamber and a barrel and the whole thing is sealed (assuming the cartridge case obturates and seals the back end) and this is EXTREMELY helpful because all of the pressure, even when your load has built precious too little of it, is directed toward moving that bullet out of the barrel. Basically:

your pistol will fail to extract or fail to eject or fail to feed (MOST LIKELY) long before you ever have a situation where the bullet is stuck in the bore.

This is great because it helps you very much to "be vigilant" and notice, inspect and clear that bore as you are experimenting.

Now finally :D my point!
Revolvers are not as kind!
The flash gap in a revolver is a pressure bleed off FROM HELL and if the load is too light, the bullet may get some distance down the bore and say "hmmm, NO!" and the pressure, which would otherwise burp it out of the way... leaks out the cylinder gap.

Sticking bullets in revolver bores is -FAR- more common and easy a trap to fall in to.

So while you are playing with "too light" loads in 9mm, please be sure to approach revolvers in a totally different mindset. Also remember that 9mm is a 35k PSI Max round and .38 Special is nearly half that. If you start making some "too light" .38 Special loads, you can really put yourself in a hole quickly with a stuck bullet.

If I seem passionate on the subject, it's because I am. I've stuck three over the years. Diligence has helped me to never take another shot, and I've also worked very hard to examine WHY these things happened and great ways to avoid them. I hope to never stick a fourth bullet and I believe my chances of doing so have dropped as I have grown more observant of the path that has led me to sticking them.
 
Stopping a couple of tenths away from maximum isn't necessary. Isn't unsafe either though.
That strange detonation issue is the result of loads that are considerably below minimum. Regardless of the type of powder.
Just follow your manual and you'll be fine. If you want a lighter load, go with a cast bullet. Been using cast 121 grain bullet with Bullseye for eons out of my BHP. Cycles 100% reliably and isn't in any way fierce recoiling.
 
I'm not so much interested in plumbing new lows (so to speak) as making sure there are no unexpected surprises if I throw a short charge.
Click to expand...

Just a couple of comments from a guy who might be the least experienced here:

If you load too lightly, the outside of your cases will show a lot of soot because they do not obturate well. The same soot has to be cleaned from your pistol. Send it out the muzzle.

One of the least-discussed but most useful reloading accessories is a good light. Unless you are already loading very lightly, pushing the lower boundaries of good function, a powder charge short enough to cause a squib will be visible to the naked eye, if you can see down into the case.
 
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